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68 Cards in this Set

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Electric circuit
circuit: an electrical device that provides a path for electrical current to flow
Charged
of a particle or body or system; having a net amount of positive or negative electric charge; "charged particles"; "a charged battery" - having an electric charge

Neutral
description of an object that has equal amounts of positive and negative charges
Electric current
steady flow of charged particles
Static electricity
an imbalance of electrons. Stationary electric charge, typically produced by friction, that causes sparks or crackling or the attraction of dust or hair


Unbalanced charges
atoms with unbalanced charges are called ions; an imbalance of charges is also known as static electricity
Laws of Charges
1. Opposite charged objects attract.
2. Charged objects attract neutral objects
3. Like charged objects repel.
Insulators
electrons are allowed little movement. They have tightly bound valence electrons (ex. Glass)
Conductors
electrons are free to move easily - 2 types of conductors.
most metals are conductors and non-metals are insulators (ex. copper)
Semiconductors
they have almost no resistance to electron flow - a material, having a conductivity greater than an insulator but less than a good conductor
Superconductors
offer little, if any, resistance to the flow of electrons - great conductor
Grounding
we ground objects by connecting them to the Earth with a wire. When an electrical discharge occurs - this can be dangerous to we ground these objects.
Battery
set of cells connected together
Switch
A device for making and breaking the connection in an electric circuit
___/ ____
Electrostatic discharge
sudden transfer of electrical charge from one object to another, indicated by a spark
Loads
device in a circuit that converts electrical energy to another form of energy (ex. light bulb)
Voltage
a measure of how much electrical energy a charged particle carries
Amperes
the unit of electrical current
Galvanometer
device for detecting and measuring small electric currents
Ammeter
meter used to measure electrical current in amperes
Potential difference
change in the potential energy of electric charge compared to its potential energy at a reference point, such as the ground; voltage
Resistance
measure of how difficult it is for electorns to flow through a substance; unit of measure is the ohm
Ohm
the unit of resistance
Ohm's law
law stating that, as long as the temperature remains constant, the resistance of a conductor remains constant, and the current is directly proportional to the voltage applied: R=V/I, I=V/R, V=IR
Series circuit
circuit in which there is only a single pathway for the current so the same current passes through all the components
Parallel circuit
circuit in which the current can flow in two or more paths
Electric energy
energy of charged particles; transferred when electrons travel from place to place
Heat
The quality of being hot; high temperature
Thermocouple
device consisting of two wires of different metals joined such that a voltage is produced between the ends in proportion in the difference in their temperatures - converts thermal energy into electrical energy
Thermo-electric generator
device based on a thermocouple that converts heat directly into electricity without moving parts.
Thermopile
Several thermocouples connected in a series
Piezoelectric effect
produces sound by converting electricity into motion (vibrations)
Photovoltaic cell (PV)
solar cell: a cell that converts solar energy into electrical energy
Electrodes
conductor through which electric current enters or leaves a device or material
Electrolyte
liquid or paste that conducts electricity because it contains ions
Fuel cell
primary cell that generates electricity directly from a chemical reaction with a fuel
Electric generator
device that converts mechanical energy (energy of motion – ex. windmills) into electrical energy
Magnetism
A physical phenomenon produced by the motion of electric charge, resulting in attractive and repulsive forces between objects


Electromagnet
coil of insulated wire (usually wrapped around a soft iron core) that becomes a magnet when current flows through it
Domains
A discrete region of magnetism in ferromagnetic material
Alternating current (AC)
current that flows back and forth 60 times per second; this is the current used in homes
Alternators
A generator that produces an alternating current
Direct current (DC)
current that flows in only one direction
Power
rate at which a device converts energy
Watt
the unit of power, equal to one joule per second
Dynamo
a machine for converting mechanical energy into electrical energy; a generator


Hydro-electric plants
Plant that generates mechanical energy and then electricity by converting the energy of moving water.
Non-renewable resources
a resource, such as coal or natural gas, that cannot be replenished
Fission products
radionuclide produced directly or indirectly by nuclear fission
Nuclear fission
splitting of atoms, which transforms them into lighter elements and releases large amounts of energy
Thermonuclear
relating to or using nuclear reactions that occur only at very high temperatures
Flare gas
Unwanted natural gas that is disposed of by burning as it is released from an oil field or at gas processing plants.
Rotor
the rotating armature of a motor or generator

Stator
mechanical device consisting of the stationary part of a motor or generator in or around which the rotor revolves
Transformers
device usually with three layers arranged such that a small voltage through the middle layer controls a current between the outer layers, allowing the device to act as a switch or amplifier.
Circuit breakers
special wire that heats up and turns off switch when excess current flows through an electrical circuit
Fuse
thin piece of metal that melts to break an electrical circuit when excess current flow occurs
Neutral wire
a conductor that carries current from an outlet back to ground, clad in white insulation.
Hot wire
The wire that carries electrical energy to a receptacle or other device—in contrast to a neutral, which carries electricity away again. Normally the black wire. Also see Ground.
Ground wire
wire (that carries no current) that runs from the fixture to metal attached to nonmetal material to ground the current in case of a short (Ground wire is usually bare copper or green).
Short circuit
accidental low-resistance connection between two points in a circuit, often causing excess current to flow
Open pit mining
A form of operation designed to extract minerals that lie near the surface. Waste, or overburden is first removed and the mineral is broken and loaded.
Scrubbers
an air pollution control device that uses a high energy liquid spray to remove aerosol and gaseous pollutants from an air stream. The gases are removed either by absorption or chemical reaction.
Greenhouse gases
gases in Earth's atmosphere that trap the heat that forms when radiant energy from the Sun reaches Earth's surface
ex. water vapour, carbon dioxide, methane and nitrogen oxide
Thermal pollution
harm to lakes and rivers resulting from the release of excessive waste heat into them
Cogeneration
use of waste energy from a process for another purpose, such as heating or generating electricity
Geothermal energy
energy derived from the internal heat of earth
Resistor
allow electrons to flow, but provides some resistances (in between)